The present invention relates to an apparatus for reducing the exhaust noise of internal combustion engines, thermodynamic equipment, and similar devices by means of so-called silators.
U.S. Pat. No. 4,149,612, issued Apr. 17, 1979, is based on German Pat. No. 2,632,290 and generally describes the construction details of silators. Basically, a silator comprises an evacuated volume enclosed between two relatively flexible, vaulted walls. The resonance frequency of such silators depends on the dimensions such as the diameter and the vaulting height.
So-called mufflers have been suggested heretofore in many variations for the damping or deadening of the exhaust noise of internal combustion engines and the like. All prior art mufflers are based on the same relatively few basic principles employing primarily noise absorption systems including materials with open pores. Other prior art systems achieve a noise insulation by means of resonating volumes including impedance breaks which are tuned relative to each other with regard to the resonance frequencies or the frequencies at which the impedance break takes place. All prior art devices require a relatively large structure. Besides, prior art mufflers are subject to very strong corrosion effects as well as to chemical conversion of the absorption materials.